CN114685079A - Slow-release air-entraining type nano porous composite material and preparation method and application thereof - Google Patents
Slow-release air-entraining type nano porous composite material and preparation method and application thereof Download PDFInfo
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- C04B2103/00—Function or property of ingredients for mortars, concrete or artificial stone
- C04B2103/30—Water reducers, plasticisers, air-entrainers, flow improvers
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Abstract
The invention discloses a slow-release air-entraining nano porous composite material and a preparation method thereof. The slow-release air-entraining nano-porous composite material comprises a nano-porous material and an air entraining agent coated by the nano-porous material; wherein the nanoporous composite material has channels for escape of air entraining agent. The invention prepares the nano-porous composite material formed by the air entraining agent and the nano-porous material by a sol-gel method, and ensures that molecules of the air entraining agent escape at a certain speed by regulating and controlling the particle size and the pore size of the nano-porous composite material, thereby realizing the purpose of slowly releasing the air entraining. The invention also provides the application of the nano-porous composite material in concrete, when the nano-porous composite material is applied to the concrete, the nano-porous composite material can slowly release the air entraining agent in the concrete stirring so that the concrete still keeps higher air content in the middle and later mixing periods, thereby achieving the purpose of long-acting bubble stabilization; meanwhile, the nano porous material in the slow-release air-entraining nano porous composite material does not influence the concrete.
Description
Technical Field
The invention belongs to the technical field of building material additives, and particularly relates to a slow-release air-entraining nano porous composite material, a preparation method thereof and application thereof in the field of concrete.
Background
With the rapid development of infrastructure construction in China, concrete is used as one of the most important engineering materials in the construction of modern civil engineering facilities, and the market has higher and higher requirements on the comprehensive properties of the concrete, such as the workability, the durability, the constructability and the like. During the mixing of concrete, it is generally necessary to incorporate air-entraining agents. The air entraining agent can introduce a proper amount of tiny, uniform and closed air bubbles into the newly-mixed and hardened concrete, thereby improving the workability, durability and frost thawing resistance of the concrete. The air entraining agent is a surfactant having a hydrophilic-lipophilic balance (HLB) within a certain range in terms of structure, that is, an amphiphilic molecule having a hydrophobic group at one end and a hydrophilic group at the other end. The commonly used air entraining agents at present comprise rosin air entraining agents, saponin air entraining agents, alkyl sulfonate air entraining agents and the like.
However, at present, the components of modern cement and concrete are complex and various, and due to the influence of salt ions and adsorption, the traditional air entraining agent can only introduce more air bubbles at the initial stage, and is easy to crack and uneven in size, so that the air content at the later stage is insufficient, and the performances of freeze thawing resistance, strength, durability and the like of the hardened concrete are influenced. At present, domestic researchers generally adopt a plurality of components to compound together to develop an air entraining agent with better performance, but the method can generate precipitation due to the instability of the two components and can also cause influence on the strength of concrete. The disadvantages of the conventional air entraining agents are also overcome by improving the conventional structure of the surfactant, but the improvement method is generally prepared by chemical synthesis, the preparation method is complicated, and the chemical component residue can affect the durability of the material.
At present, a method for preparing the air entraining agent microcapsule by stirring ethyl cellulose and sodium dodecyl benzene sulfonate in an ethanol solution is reported, and the slow release of the air entraining agent is controlled by controlling the rupture time of the microcapsule; however, the air entraining agent microcapsule obtained by the method has the defect that the rupture time of the microcapsule is difficult to control and the air entraining agent is only adsorbed on the surface of the ethyl cellulose and is released in the initial stage during application, so that the effect of slowly releasing the air entraining agent cannot be achieved.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a slow-release air-entraining type nano porous composite material, which can achieve the purpose of slowly releasing the air entraining agent in the nano porous composite material by controlling the aperture of the nano porous composite material.
In order to achieve the purpose of the invention, the invention adopts the following technical scheme:
the slow-release air-entraining nano-porous composite material comprises an air entraining agent formed by coating a nano-porous material with the nano-porous material; the slow-release air entraining type nano porous composite material is provided with a channel for the escape of the air entraining agent, and the pore size of the channel is 1 nm-20 nm.
Further, the nano-porous material is nano titanium dioxide or nano silicon dioxide.
Further, the air entraining agent is selected from any one of an anionic air entraining agent, a cationic air entraining agent, a zwitterionic air entraining agent and a nonionic air entraining agent.
Further, the anionic air entraining agent is selected from any one of alkyl sulfate air entraining agents, alkyl sulfonate air entraining agents, alkyl benzene sulfonate air entraining agents, alkyl polyoxyethylene ether sulfate air entraining agents, sulfosuccinate air entraining agents and rosin saponin air entraining agents; the cationic air entraining agent is selected from any one of alkyl trimethyl ammonium bromide; the zwitterionic air entraining agent is selected from any one of alkyl sulphobetaine and amine oxide air entraining agents; the non-ionic air entraining agent is selected from any one of alkyl polyoxyethylene ether air entraining agents, alkylphenol polyoxyethylene ether air entraining agents and alkyl glycoside air entraining agents.
Further, the particle size of the slow-release air-entraining nano-porous composite material is 50 nm-500 nm.
Another object of the present invention is to provide a method for preparing the slow release air-entraining type nano-porous composite material, which comprises the following steps:
s1, uniformly dispersing the air entraining agent and the alkali liquor in the alcohol solvent to obtain an air entraining agent solution;
s2, dropping an inorganic precursor into the air-entraining agent solution, fully stirring, taking air-entraining agent micelles in the air-entraining agent solution as growth points, hydrolyzing the inorganic precursor under the action of the alkali liquor, and carrying out sol-gel reaction to generate a nano porous material;
s3, continuously stirring the reaction system in the step S2 for 2-5 hours, then carrying out solid-liquid separation, washing and drying the obtained filter cake, and obtaining the slow-release air-entraining type nano porous composite material;
wherein the mass ratio of the air entraining agent, the alkali liquor and the inorganic precursor is 10-50: 0.05-0.8: 1.
Further, the alkali liquor is selected from any one of ammonia water, triethanolamine, tetraethylammonium hydroxide and tetramethylammonium hydroxide.
Further, the inorganic precursor is selected from tetraethyl orthosilicate, methyl orthosilicate, butyl orthosilicate, tetraethyl titanate, or tetrabutyl titanate.
The invention also aims to provide application of the slow-release air-entraining nano-porous composite material, which is prepared by mixing the slow-release air-entraining nano-porous composite material with cement and concrete raw materials and stirring to obtain concrete; wherein the dosage of the slow-release air-entraining nano porous composite material is 0.01-0.1% of the mass of the cementing material in the concrete.
The invention designs a nano-porous composite material formed by a nano-porous material and an air entraining agent coated by the nano-porous material, which is prepared by a sol-gel method, and ensures that molecules of the air entraining agent escape at a certain speed by regulating the particle size and the pore size of the nano-porous composite material, thereby realizing the purpose of slowly releasing air entraining. When the slow-release air-entraining nano porous composite material is applied to concrete, the air-entraining agent can be slowly released in the concrete stirring process, so that the concrete still keeps higher air content in the middle and later mixing period, the aim of stabilizing bubbles for a long time is fulfilled, and the freeze-thaw resistance of the concrete is improved; meanwhile, the nano porous material in the slow-release air-entraining nano porous composite material does not cause adverse effect on the concrete material.
Drawings
The above and other aspects, features and advantages of embodiments of the present invention will become more apparent from the following description taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a schematic diagram of the preparation and slow release principle of a slow release air entraining type nanoporous composite material according to the invention; wherein 1 represents an air entraining agent, 2 represents a nano porous material, and 21 represents a channel;
FIG. 2 is a particle size distribution plot of the product of example 1 according to the present invention;
FIG. 3 is a particle size distribution plot of the product of example 2 according to the present invention;
FIG. 4 is a particle size distribution plot of the product of example 3 according to the present invention;
FIG. 5 is a particle size distribution plot of the product of example 4 according to the present invention;
FIG. 6 is a particle size distribution plot of the product of example 5 according to the present invention;
FIG. 7 is a particle size distribution diagram of the product of example 6 according to the present invention.
Detailed Description
Hereinafter, embodiments of the present invention will be described in detail with reference to the accompanying drawings. This invention may, however, be embodied in many different forms and should not be construed as limited to the specific embodiments set forth herein. Rather, these embodiments are provided to explain the principles of the invention and its practical application to thereby enable others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. In the drawings, the shapes and sizes of elements may be exaggerated for clarity, and the same reference numerals will be used throughout to designate the same or similar elements.
It should be noted that the terms "comprises," "comprising," and "having," and any variations thereof, are intended to cover non-exclusive inclusions, such that a process, method, system, article, or apparatus that comprises a list of steps or elements is not necessarily limited to those steps or elements expressly listed, but may include other steps or elements not expressly listed or inherent to such process, method, article, or apparatus.
Based on the current situation that the general air entraining agent in the prior art can not realize the purpose of slow release, the inventor of the invention researches and develops a slow release air entraining type nano porous composite material, and the effect of slow release of the air entraining agent molecules is realized by controlling the aperture and the particle size of the nano porous composite material.
Specifically, the slow-release air-entraining nano-porous composite material comprises a nano-porous material and an air-entraining agent coated by the nano-porous material; wherein, the nano-porous composite material is provided with a channel with the aperture size of 1 nm-20 nm for the escape of the air entraining agent.
In the slow-release air entraining type nano porous composite material, the nano porous material is nano titanium dioxide or nano silicon dioxide, and the air entraining agent can be any one of an anionic air entraining agent, a cationic air entraining agent, a zwitterionic air entraining agent and a nonionic air entraining agent, and is preferably an anionic air entraining agent.
Further, the anionic air-entraining agent may be any one selected from an alkylsulfate air-entraining agent, an alkylsulfonate air-entraining agent, an alkylbenzenesulfonate air-entraining agent, an alkylpolyoxyethylene ether sulfate air-entraining agent, a sulfosuccinate air-entraining agent, and a rosin saponin air-entraining agent; wherein the alkyl group is preferably dodecyl. The cationic air entraining agent can be selected from any one of alkyl trimethyl ammonium bromide; the zwitterionic air entraining agent can be selected from any one of alkyl sulfobetaine and amine oxide air entraining agent; the nonionic air-entraining agent may be any one selected from among an alkyl polyoxyethylene ether air-entraining agent, an alkyl phenol polyoxyethylene ether air-entraining agent, and an alkyl glycoside air-entraining agent.
The particle size of the slow-release air-entraining nano-porous composite material is generally 50 nm-500 nm; the particle size will influence the release efficiency to a certain extent, i.e. a larger particle size will generally have a larger pore size, whereby the escape rate of the air-entraining agent from the interior thereof will be relatively large.
The slow-release air-entraining nano-porous composite material can be prepared by adopting the following preparation method:
firstly, uniformly dispersing an air entraining agent and alkali liquor in an alcohol solvent to obtain an air entraining agent solution.
Specifically, the alkali solution is selected from any one of ammonia water, triethanolamine, tetraethylammonium hydroxide, and tetramethylammonium hydroxide.
Then, dropping an inorganic precursor into the air-entraining agent sol, fully stirring, taking the air-entraining agent micelle in the air-entraining agent solution as a growth point, hydrolyzing the inorganic precursor under the action of alkali liquor, and carrying out sol-gel reaction to generate the nano porous material.
Specifically, the inorganic precursor is selected from any one of tetraethyl orthosilicate, methyl orthosilicate, butyl orthosilicate, tetraethyl titanate, and tetrabutyl titanate.
In the two steps, the ratio of the amount of the air entraining agent, the alkali liquor and the inorganic precursor is controlled to be 10-50: 0.05-0.8: 1. The control of the alkali liquor dosage is important for the slow release performance influence of the slow release air entraining type nano porous composite material, which determines the pore size of the nano porous composite material obtained by hydrolyzing the inorganic precursor, obviously, if the pore size is too small, the air entraining agent in the nano porous composite material cannot be smoothly released, and if the pore size is too large, the slow release effect cannot be achieved due to too fast release, which is the same as the conventional air entraining agent in the prior art.
And finally, continuously stirring the reaction system obtained in the second step for 2-5 h, performing solid-liquid separation, washing and drying the obtained filter cake, and obtaining the slow-release air-entraining type nano porous composite material.
Fig. 1 shows a sol-gel process for preparing the slow-release air-entraining nano-porous composite material and a principle of the slow-release process, namely, an inorganic precursor is hydrolyzed under the action of alkali liquor, and nano silicon dioxide or titanium dioxide is generated through a sol-gel reaction, wherein the nano silicon dioxide or titanium dioxide has a three-dimensional network structure, has a large specific surface area, has a large amount of hydroxyl groups on the surface, is strong in hydrophilicity, is in a chain shape by linking a plurality of particles, continues to grow in a combined manner under the action of hydrogen bonds between the chain structures and air-entraining agent molecular micelles, and is automatically combined to grow into a porous sphere with a three-dimensional network structure, so that the slow-release air-entraining nano-porous composite material is prepared.
The above-mentioned slow release air entraining type nanoporous composite material and the preparation method thereof according to the present invention will be embodied by the following specific examples, but those skilled in the art will appreciate that the following examples are only specific examples of the slow release air entraining type nanoporous composite material and the preparation method thereof according to the present invention, and are not intended to limit the entirety thereof.
Example 1
First, 10mol of sodium lauryl sulfate (anionic air-entraining agent) and 0.15mol of ammonia water were added to 100g of ethanol with stirring to obtain a sodium lauryl sulfate solution.
And then, 0.5mol of tetraethyl orthosilicate is dropwise added into the obtained sodium dodecyl sulfate solution, the mixture is fully stirred at the temperature of 25 ℃, sodium dodecyl sulfate micelles in the sodium dodecyl sulfate solution are taken as growth points in the reaction system, the tetraethyl orthosilicate is hydrolyzed under the action of ammonia water, and sol-gel reaction is carried out to generate the porous nano silicon dioxide.
And finally, continuously stirring the reaction system obtained after the tetraethyl orthosilicate is dropwise added in the second step for 3 hours, carrying out solid-liquid separation, washing the obtained filter cake with ethanol for several times to remove the sodium dodecyl sulfate attached to the surface of the porous nano-silica, and drying to obtain the nano-porous composite material formed by the sodium dodecyl sulfate and the porous nano-silica.
That is, the present embodiment provides a nanoporous composite material using sodium dodecyl sulfate as an air entraining agent and porous nanosilicon dioxide as a coating.
The pore size of this nanoporous composite was measured by nitrogen adsorption specific surface area analyzer (BET) and the average pore size was 8nm, i.e. the pore size of the channels in the nanoporous composite was 8 nm.
The particle size of the nanoporous composite material was examined by Dynamic Light Scattering (DLS) and the particle size distribution of the nanoporous composite material is shown in fig. 2. The particle size of the obtained slow-release air-entraining nano-porous composite material is about 200nm, the particle size distribution is narrow, and the dispersibility is good.
Example 2
First, 2mol of sodium lauryl sulfate (anionic air-entraining agent) and 0.01mol of aqueous ammonia were added to 100g of ethanol with stirring to obtain a sodium lauryl sulfate solution.
Then, 0.2mol of methyl orthosilicate is dripped into the obtained lauryl sodium sulfate solution and fully stirred at the temperature of 20 ℃, lauryl sodium sulfate micelles in the lauryl sodium sulfate solution are taken as growing points in the reaction system, the methyl orthosilicate is hydrolyzed under the action of ammonia water and is subjected to sol-gel reaction, and the porous nano silicon dioxide is generated.
And finally, continuously stirring the reaction system obtained after the methyl orthosilicate is dropwise added in the second step for 5 hours, carrying out solid-liquid separation, washing the obtained filter cake with ethanol for several times to remove the sodium dodecyl sulfate attached to the surface of the porous nano-silica, and drying to obtain the nano-porous composite material formed by the sodium dodecyl sulfate and the porous nano-silica.
That is, the present embodiment provides a porous nanocomposite material using sodium dodecyl sulfate as an air entraining agent and porous nano-silica as a coating.
The pore size of this nanoporous composite was tested by nitrogen adsorption specific surface area analyzer (BET) and the average pore size was 1nm, i.e., the pore size of the channels in the nanoporous composite was 1 nm.
The particle size of the nanoporous composite material was examined by Dynamic Light Scattering (DLS) and the particle size distribution of the nanoporous composite material is shown in fig. 3. It can be seen that the particle size of the obtained slow-release air-entraining nano-porous composite material is about 50 nm.
Example 3
Firstly, 30mol of sodium dodecyl polyoxyethylene ether sulfate (anionic air entraining agent) and 0.8mol of ammonia water are added into 100g of ethanol under stirring to obtain a sodium dodecyl polyoxyethylene ether sulfate solution.
Then, 1.0mol of n-butyl silicate is dripped into the obtained sodium dodecyl polyoxyethylene ether sulfate solution, the mixture is fully stirred at the temperature of 30 ℃, the sodium dodecyl polyoxyethylene ether sulfate micelles in the sodium dodecyl polyoxyethylene ether sulfate solution are taken as growing points in the reaction system, the n-butyl silicate is hydrolyzed under the action of ammonia water, and sol-gel reaction is carried out, thus generating the porous nano silicon dioxide.
And finally, continuously stirring the reaction system obtained after the dropwise addition of the n-butyl silicate in the second step for 5 hours, carrying out solid-liquid separation, washing the obtained filter cake with ethanol for several times to remove the sodium dodecyl polyoxyethylene ether sulfate attached to the surface of the porous nano-silica, and drying to obtain the nano-porous composite material formed by the sodium dodecyl polyoxyethylene ether sulfate and the porous nano-silica.
That is, the present embodiment provides a nanoporous composite material using sodium dodecyl polyoxyethylene ether sulfate as an air-entraining agent and porous nanosilicon dioxide as a coating.
The pore size of this nanoporous composite was measured by nitrogen adsorption specific surface area analyzer (BET) and the average pore size was 20nm, i.e. the pore size of the channels in the nanoporous composite was 20 nm.
The particle size of the nanoporous composite material was examined by Dynamic Light Scattering (DLS) and the particle size distribution of the nanoporous composite material is shown in fig. 4. It can be seen that the particle size of the obtained slow-release air-entraining nano-porous composite material is about 500 nm.
Example 4
Firstly, 10mol of dodecyl trimethyl ammonium bromide (cationic air entraining agent) and 0.2mol of triethanolamine are taken and added into 100g of ethanol under stirring to obtain dodecyl trimethyl ammonium bromide solution.
Then, 0.5mol of tetraethyl titanate is dripped into the obtained dodecyl trimethyl ammonium bromide solution and fully stirred at the temperature of 23 ℃, the dodecyl trimethyl ammonium bromide micelle in the dodecyl trimethyl ammonium bromide solution is taken as a growth point in the reaction system, the tetraethyl titanate is hydrolyzed under the action of triethanolamine and is subjected to sol-gel reaction, and the porous nano titanium dioxide is generated.
And finally, continuously stirring the reaction system obtained after the dropwise addition of the tetraethyl titanate in the second step for 5 hours, carrying out solid-liquid separation, washing the obtained filter cake with ethanol for a plurality of times to remove the dodecyl trimethyl ammonium bromide attached to the surface of the porous nano titanium dioxide, and drying to obtain the nano porous composite material formed by the dodecyl trimethyl ammonium bromide and the porous nano titanium dioxide.
That is to say, the embodiment provides a nano-porous composite material using dodecyl trimethyl ammonium bromide as an air entraining agent and porous nano titanium dioxide as a coating.
The pore size of this nanoporous composite was measured by nitrogen adsorption specific surface area analyzer (BET) and the average pore size was 15nm, i.e. the pore size of the channels in the nanoporous composite was 15 nm.
The particle size of the nanoporous composite material was examined by Dynamic Light Scattering (DLS) and the particle size distribution of the nanoporous composite material is shown in fig. 5. It can be seen that the particle size of the obtained slow-release air-entraining nano-porous composite material is about 250 nm.
Example 5
First, 10mol of laurylamidopropylamine oxide (zwitterionic air-entraining agent) and 0.24mol of tetraethylammonium hydroxide were added with stirring to 100g of ethanol to obtain a laurylamidopropylamine oxide solution.
Then, 0.8mol of tetrabutyl titanate is dripped into the obtained lauric acid amide propyl amine oxide solution, the mixture is fully stirred at the temperature of 26 ℃, the lauric acid amide propyl amine oxide micelle in the lauric acid amide propyl amine oxide solution is taken as a growth point in the reaction system, tetrabutyl titanate is hydrolyzed under the action of tetraethylammonium hydroxide, and sol-gel reaction is carried out, so that the porous nano titanium dioxide is generated.
And finally, continuously stirring the reaction system obtained after the dropwise addition of the tetrabutyl titanate in the second step for 3.5 hours, carrying out solid-liquid separation, washing the obtained filter cake with ethanol for several times to remove the lauric acid amide propyl amine oxide attached to the surface of the porous nano titanium dioxide, and drying to obtain the nano porous composite material formed by the lauric acid amide propyl amine oxide and the porous nano titanium dioxide.
That is, the present embodiment provides a nanoporous composite material using lauric acid amidopropyl amine oxide as an air-entraining agent and porous nano-titania as a coating.
The pore size of this nanoporous composite was measured by nitrogen adsorption specific surface area analyzer (BET) and the average pore size was 10nm, i.e. the pore size of the channels in the nanoporous composite was 10 nm.
The particle size of the nanoporous composite material was examined by Dynamic Light Scattering (DLS) and fig. 6 shows the particle size distribution of the nanoporous composite material. It can be seen that the particle size of the obtained slow-release air-entraining nano-porous composite material is about 230 nm.
Example 6
Firstly, 10mol of lauryl polyoxyethylene ether (nonionic air entraining agent) and 0.12mol of tetramethylammonium hydroxide are taken and added into 100g of ethanol under stirring to obtain lauryl polyoxyethylene ether solution.
Then, 0.6mol of tetraethyl orthosilicate is dripped into the obtained lauryl polyoxyethylene ether solution and fully stirred at the temperature of 28 ℃, tetraethyl orthosilicate is hydrolyzed under the action of tetramethylammonium hydroxide by taking lauryl polyoxyethylene ether micelles in the lauryl polyoxyethylene ether solution as growth points in the reaction system, and sol-gel reaction is carried out to generate the porous nano-silica.
And finally, continuously stirring the reaction system obtained after the tetraethyl orthosilicate is dropwise added in the second step for 4.5 hours, then carrying out solid-liquid separation, washing the obtained filter cake with ethanol for several times to remove the lauryl alcohol polyoxyethylene ether attached to the surface of the porous nano-silica, and drying to obtain the nano-porous composite material formed by the lauryl alcohol polyoxyethylene ether and the porous nano-silica.
That is, the present embodiment provides a nanoporous composite material using lauryl polyoxyethylene ether as an air entraining agent and porous nanosilicon dioxide as a coating.
The pore size of this nanoporous composite was measured by nitrogen adsorption specific surface area analyzer (BET) and the average pore size was 5nm, i.e. the pore size of the channels in the nanoporous composite was 5 nm.
The particle size of the nanoporous composite material was examined by Dynamic Light Scattering (DLS) and the particle size distribution of the nanoporous composite material is shown in fig. 7. It can be seen that the particle size of the obtained slow-release air-entraining nano-porous composite material is about 170 nm.
In the slow-release air-entraining type nano porous composite material prepared based on the sol-gel method, the porous characteristic is very important for realizing the slow release effect, and in order to reflect the influence of the structure on the performance of the composite material, pure lauryl sodium sulfate, lauryl trimethyl ammonium bromide, lauric acid amide propyl amine oxide and lauryl alcohol polyoxyethylene ether are respectively provided, and are respectively compared with the examples 1 and 4-6, and are sequentially used as comparative examples 1-4. Meanwhile, the order of addition of the raw materials in the above preparation method also plays an important role in whether the slow-release air-entraining nanoporous composite material can be synthesized, and for this reason, the following comparative experiment was performed in comparison with the preparation method in example 1.
Comparative example 5
Firstly, 0.15mol of ammonia water is taken and added into 100g of ethanol under stirring, 0.5mol of tetraethyl orthosilicate is dropwise added into the ethanol, and the tetraethyl orthosilicate is hydrolyzed under the action of the ammonia water to generate the nano porous silicon dioxide.
Then, stirring the nanoporous silica and 10mol of sodium dodecyl sulfate (anionic air entraining agent, 0.05mol/mL solution) in a beaker for 12h, allowing the sodium dodecyl sulfate to enter the nanoporous silica and reach equilibrium, washing with ethanol to remove the sodium dodecyl sulfate attached to the surface of the nanoporous silica, and drying to obtain the comparative composite air entraining agent.
In order to verify the slow release effect of the slow release air entraining type nano porous composite material provided in each of the above embodiments of the present invention, an organic carbon desorption test was performed to investigate the slow release effect. The instrument used was a Muti Toc 3000Analyzer Total organic carbon Analyzer from Jiangsu Su Bordete New materials GmbH.
Meanwhile, the comparative air entraining agents provided in the comparative examples 1 to 5 were also tested correspondingly.
The specific test operations were as follows: weighing 0.3g of each composite material in examples 1-6 and each comparative air-entraining agent in comparative examples 1-5, dissolving in 150g of water, stirring, taking 10g of supernatant in 0h, 0.25h, 0.5h, 1h, 1.5h, 2h and 3h respectively, adding 1g of 1mol/L HCl, and testing the content of organic matters in the slowly released air-entraining agent.
Table 1 shows the TOC values at different times for each composite material in the examples described above and for each comparative air-entraining agent in the comparative examples.
TABLE 1 TOC values at different times for each of the composite materials of examples 1-6 and for each of the comparative air-entraining agents of comparative examples 1-5
In table 1, each data unit is desorption amount (g)/1g of the slow-release air-entraining nanoporous composite material or the air-entraining agent; the denominator part in examples 1-6 shows the slow-release air-entraining nano porous composite material, the denominator part in comparative examples 1-4 shows the air entraining agent, and the denominator part in comparative example 5 shows the comparative composite air entraining agent.
As can be seen from table 1, the amount of the desorbed air-entraining agent of the slow-release air-entraining nano-porous composite materials provided in embodiments 1 to 6 of the present invention gradually increases with the time, which indicates that the slow-release air-entraining nano-porous composite materials have an obvious slow-release effect. The pure air entraining agents provided in the comparative examples 1 to 4 have high TOC values in the initial stage, and the TOC values are not changed along with the prolonging of time, which shows that the slow release effect does not exist when the air entraining agents are directly used. The comparative composite air entraining agent obtained in the comparative example 5 has a lower TOC value all the time and does not exhibit the effect of gradually desorbing the air entraining agent, that is, it does not have a slow release effect, and it is found by analysis that the TOC value is always lower because the way of preparing the nanoporous silica in advance and then adsorbing the air entraining agent, and the TOC value cannot allow the air entraining agent to enter the interior of the nanoporous silica through the channel, and the TOC value is only adsorbed on the surface of the nanoporous silica and is removed by the final washing process, that is, the product obtained in the comparative example 5 is substantially the nanoporous silica with a small amount of air entraining agent adsorbed on the surface, and is not the composite air entraining agent in a strict sense.
Meanwhile, compared with the slow release effect of the slow release air entraining type nano-porous composite material in each embodiment at the same time, the slow release speed of the product obtained when the using amount of the ammonia water used in the preparation is larger is found to be higher, because more ammonia water can obtain the nano-porous composite material with larger size, namely the particle size and the pore size of the channel are larger.
The slow-release air-entraining nano porous composite material provided by the invention can be well applied to the preparation of concrete and provides a good slow-release effect. Generally, concrete can be obtained by preparing and stirring the slow-release air-entraining nano-porous composite material with cement and concrete raw materials.
The dosage of the common slow-release air entraining type nano porous composite material is controlled to be 0.01-0.1 percent of the mass of the cementing material in the concrete.
The following application experiments are performed on the application of the slow-release air-entraining nano-porous composite material obtained in each of the above embodiments in concrete.
Application examples
The slow-release air-entraining nano-porous composite materials in the above examples 1 to 6 were prepared into concrete by using the concrete mixing ratio shown in table 2 below.
TABLE 2 concrete mix proportions
The cement used is P.II 52.5 cement of small open field in south of the Yangtze river, the sand is medium sand with fineness modulus Mx of 2.7, and the coarse aggregate is 5 mm-20 mm continuous graded broken stone. The used polycarboxylic acid water reducing agent is provided by Jiangsu Subo new materials Co. The test is carried out according to the conditions and the method specified in GB8076-2008, and the doping amount of all the slow-release air-entraining nano porous composite materials or the air entraining agents or the comparative composite air entraining agents is the same and is kept to be 0.6 ten thousandth of the mass of the adhesive material.
The air contents of the concrete obtained by the slow-release air-entraining nano-porous composite material in each example, the air entraining agents in the comparative examples 1 to 4 and the comparative composite air entraining agent in the comparative example 5 at different times were tested, and the test results are shown in table 3.
TABLE 3 test results of the gas content of the concrete at different times for each of the composite materials and the comparative material
As can be seen from table 3, the concrete prepared by using the slow-release air-entraining type nanoporous composite material in the above embodiment of the invention has a gradually increased air content in the concrete with the passage of time, i.e. the loss of the air content in the concrete is obviously increased; the slow-release air entraining agent starts to entrain air in the later period, so that the loss of air content of concrete in the later period is improved, and the freeze-thaw resistance of the concrete can be improved. The concrete prepared by the pure air entraining agent in the comparative examples 1-4 has obvious air entraining effect at the beginning, and the air entraining capability is that anion is greater than zwitterion is greater than nonionic is greater than cation, but the slow release effect is not achieved along with the prolonging of time. Meanwhile, the concrete prepared by the comparative composite air entraining agent obtained in the comparative example 5 cannot release the air entraining agent according to the data in the table 1, and thus cannot show a slow release effect.
All the materials used above are commercial products, wherein all reagents (analytically pure) used for preparing the slow-release air-entraining nano-porous composite material are obtained from Shanghai Aladdin Biotechnology Co., Ltd, the anionic air-entraining agent, the cationic air-entraining agent, the zwitterionic air-entraining agent and the nonionic air-entraining agent in the preparation examples, and the polycarboxylic acid water reducing agent in the application examples are obtained from Jiangsu Subot New materials Co., Ltd.
While the invention has been shown and described with reference to certain embodiments, those skilled in the art will understand that: various changes in form and details may be made therein without departing from the spirit and scope of the invention as defined by the appended claims and their equivalents.
Claims (9)
1. The slow-release air-entraining nano-porous composite material is characterized by comprising a nano-porous material and an air entraining agent coated by the nano-porous material; the slow-release air entraining type nano porous composite material is provided with a channel for the escape of the air entraining agent, and the pore size of the channel is 1 nm-20 nm.
2. The slow release air entraining nanoporous composite material according to claim 1, wherein the nanoporous material is nano titanium dioxide or nano silicon dioxide.
3. The slow-release air-entraining nanoporous composite material according to claim 1, wherein the air-entraining agent is selected from any one of an anionic air-entraining agent, a cationic air-entraining agent, a zwitterionic air-entraining agent and a non-ionic air-entraining agent.
4. The slow release air entraining type nanoporous composite material according to claim 3, wherein the anionic air entraining agent is selected from any one of alkyl sulfate type air entraining agent, alkyl sulfonate type air entraining agent, alkyl benzene sulfonate type air entraining agent, alkyl polyoxyethylene ether sulfate type air entraining agent, sulfosuccinate type air entraining agent, rosin saponin type air entraining agent; the cationic air entraining agent is selected from any one of alkyl trimethyl ammonium bromide; the zwitterionic air entraining agent is selected from any one of alkyl sulphobetaine and amine oxide air entraining agents; the nonionic air entraining agent is selected from any one of alkyl polyoxyethylene ether air entraining agents, alkylphenol polyoxyethylene ether air entraining agents and alkyl glycoside air entraining agents.
5. The slow release air entraining type nanoporous composite material according to any one of claims 1 to 4, wherein the particle size of the slow release air entraining type nanoporous composite material is 50nm to 500 nm.
6. The method for preparing the slow-release air-entraining nanoporous composite material as claimed in any one of claims 1 to 5, comprising the steps of:
s1, uniformly stirring and dispersing the air entraining agent and the alkali liquor in the alcohol solvent to obtain an air entraining agent solution;
s2, dropping an inorganic precursor into the air-entraining agent solution, fully stirring, taking air-entraining agent micelles in the air-entraining agent solution as growth points, hydrolyzing the inorganic precursor under the action of the alkali liquor, and carrying out sol-gel reaction to generate a nano porous material;
s3, continuously stirring the reaction system in the step S2 for 2-5 hours, then carrying out solid-liquid separation, washing and drying the obtained filter cake, and obtaining the slow-release air-entraining type nano porous composite material;
wherein the mass ratio of the air entraining agent, the alkali liquor and the inorganic precursor is 10-50: 0.05-0.8: 1.
7. The method according to claim 6, wherein the alkaline solution is selected from any one of ammonia water, triethanolamine, tetraethylammonium hydroxide, and tetramethylammonium hydroxide.
8. The method according to claim 6, wherein the inorganic precursor is selected from tetraethyl orthosilicate, methyl orthosilicate, butyl orthosilicate, tetraethyl titanate, and tetrabutyl titanate.
9. The use of the slow release air-entraining nanoporous composite material according to any one of claims 1 to 5, wherein the concrete is obtained by formulating and stirring the slow release air-entraining nanoporous composite material with cement and concrete raw materials; wherein the dosage of the slow-release air-entraining nano porous composite material is 0.01-0.1% of the mass of the cementing material in the concrete.
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| WO2024007681A1 (en) * | 2022-07-08 | 2024-01-11 | 石家庄市长安育才建材有限公司 | Slow-release air-entraining agent, preparation method therefor and concrete state retaining agent |
| CN117945685A (en) * | 2022-10-21 | 2024-04-30 | 博特新材料泰州有限公司 | High-stability foam air entraining agent for concrete and preparation method and application thereof |
| CN117945685B (en) * | 2022-10-21 | 2024-10-29 | 博特新材料泰州有限公司 | High-stability foam air entraining agent for concrete and preparation method and application thereof |
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